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7 sachets

This is a high quality, short term course of live cultures. 'One week flat' from OptiBac Probiotics is gluten free and therefore may be especially suitable for those with bloating.

Vegetarian Vegetarian
No Gluten No Gluten
Suitable during Pregnancy Suitable during Pregnancy

What's it for?

A natural bacteria supplement from OptiBac Probiotics to be taken for 7 consecutive days.

Who's it for?

For those seeking a high quality, short-term live cultures supplement.

Each sachet:

Provides 5 billionlive cultures + 0.3g FOS fibres.

OptiBac Probiotics 'One week flat'

'One week flat' is a food supplement containing natural bacteria (live cultures), in powdered sachets to be taken daily as a one-week course. This can be taken once a month, or as frequently as desired. Please scroll to the bottom of the page to read reviews from our customers who have tried this supplement.

Lactococcus lactis Rosell-1058

Lactococcus lactis Rosell-1058

More about 'One week flat'

Lactobacillus acidophilus Rosell-52: acidophilus is a natural resident of the intestinal microflora; this strain of acidophilus from OptiBac Probiotics has been shown to survive gastric acidity and biliary salts, and to reach the intestines without damage.

Bifidobacterium bifidum Rosell-71: In-vitro tests suggest that this strain flourishes well with Fructooligosaccharides.

Lactobacillus casei Rosell-215 is of an extensively studied species naturally residing in the intestinal flora; this strain from OptiBac Probiotics has been researched in its ability to resist gastric acidity and bile salts in order to reach your small and large intestines alive.

Lactococcus lactis Rosell-1058 is extracted from the kefir culture, and has been scientifically proven to reach the gut alive.

Fructooligosaccharide fibres (FOS) predominantly settle in the large intestine where they may act as a food source to stimulate the growth of your body's natural bacteria.

This 7 day course is ideal for those looking for a short term, high quality natural bacteria supplement.

Background information

Unlike similar foods and supplements containing live cultures, 'One week flat' is free from added sugars and does not contain gluten, and may therefore be suitable for those with bloating. Abdominal or stomach bloating is thought to be associated with food intolerances, constipation, over-eating, PMS or intestinal gas; leaving the abdomen feeling uncomfortable, full and tight. If you have poor digestion, waste materials and the gases they produce can remain in the gut for long periods of time, often at high temperatures and pressures. This causes bloating and stretching of the gut walls beyond their comfortable limits. An imbalance of bacteria in the gut may result in poor digestive health, bloating, production of smelly and uncomfortable gases, and sluggish bowels. This imbalance is known as dysbiosis.

Healthcare professionals can see Scientific Research on live cultures and bloating.

Please note: As of May 2014, this product has a new name ('One week flat') in the EU. The ingredients remain the same.


As a natural food supplement 'One week flat' can be given to adults and children from 4 years old & up, with the following recommendations: Take one sachet daily with breakfast for a 7 day course, or as professionally directed.

We highly recommend you take 'One week flat' for 7 consecutive days. Most customers take this course once a month, but it can taken as often as desired. For more information see our FAQ: How often should I take OptiBac 'One week flat'?

For best results:

  1. Pour an inch of water into a tall glass, leaving plenty of room for swirling.
  2. Shake the sachet well before gently sprinkling in the powder.
  3. Leave powder to dissolve naturally.
  4. Vigorously swirl the water around in the glass.
  5. Drink, wait, and enjoy the benefits!


It is not recommended to give live cultures to patients who are: severely immunosuppressed, have pancreatitis, are in the Intensive Care Unit, have blood in the stool, have central venous catheters; or to post-surgical patients with open wounds, or infants with short bowel syndrome; unless under a doctor's care.

Nutritional Information

Stabiliser: Maltodextrin; Fructooligosaccharides (FOS); live cultures: (Lactococcus lactis Rosell-1058, Lactobacillus casei Rosell-215, Lactobacillus acidophilus Rosell-52 and Bifidobacterium bifidum Rosell-71).

Each sachet guarantees 5 billion micro-organisms + 0.3g FOS fibres.


Like the rest of the OptiBac Probiotics range, this product does not require refrigeration.

Store away from direct sunlight.

Delivery Options

Method Price
Next Day Delivery
Choose this option by 2pm Mon-Fri and your order should be with you in 24 hours.
£6.00 *
First Class Postage
Usually delivered within 1-3 days
£2.50 *
Standard Shipping
Usually delivered within 4-7 days
£1.75 *
International - Europe
Please allow 7-10 days for delivery
£6.00 *
Please allow 7-20 days for delivery
£12.00 *
* All prices include UK value added tax. Purchases made from outside of the European Union will not incur the additional tax on delivery.
  • Having tried these before and having read the reviews I thought I'd give them another go. Like some of the other reviewers, I too suffer badly with IBS and having tried various prescribed and natural remedies hoped these would help - unfortunately they didn't. I felt no benefits whatsoever and in fact felt slightly more bloated! I'm pleased that they appear to have worked for others, just wish they'd worked for me. I'm still taking the daily probiotics but again haven't seen any positive benefits yet and my IBS is still bad and driving me nuts! Oh well, will remain positive for a miracle cure!!

  • Response from OptiBac Probiotics

    Dear Linda, I’m sorry to hear that the product was not helpful for your IBS symptoms. IBS is different for everyone, and sometimes what works for some doesn’t work for others. We’d also always underline that different probiotics will work in different ways, so it might be a case of trial and error whilst you find one for you. If you'd like to talk to our team of nutritional therapists about this further please don't hesitate to email us on [email protected] and we’d be more than happy to help / see if we can advise anything different. Best regards, Emeka.

  • I suffered from bloating for more than 5 years, with no relief whatsoever. My colonics Hydrotherapist recommended OptiBac products, that were spoken highly of at Colonics seminars. I purchased One Week Flat, and from day one of the 7 day course, I have had no bloating since. I am amazed, speechless and over the moon to be free of bloating, which caused me extreme pain sometimes, it affected me walking or exercising. It affected my relationship with my wife, it gave or worsened lower back pain that I suffer from. I am now completely free from bloating, and at risk of sounding dramatic, it has turn my life around :)))))) Sincerely, Howard

  • Cannot recommend this product enough. I am a chronic IBS sufferer and was going through a bad patch with coming off my pill (super, super bloated). After 3 days I noticed a massive difference and felt... Read more

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